Light buoys



Oct. 13, 1959 v A. K. M COSH LIGHT BUOYS Filed May 16, 1958 5 Sheets-Sheet 1 In ventor l/vmew AV/AA/WOOD MC 6066 A ttomey Oct. 13, 1959 A. K. M cosH LIGHT BUOYS Filed May 16, 1958 3 Sheets-Sheet 2 ANDREW KIM W000 M0605 Attorney Oct. 13, 1959 A. K. M cosH 2,908,810

LIGHT BUOYS 5 Filed May 16, 1958 '3 Sheets-Sheet 5' y/1411; Attorney United States Patent Ofie Patented Oct. 13, 1959 LIGHT BUOYS Andrew K. McCosh, Waltry, Milton of Campsie, Scotland Application May 16, 1958, Serial No. 735,771 Claims priority, application Great liritain June 24, 1957 V 9 Claims. (Cl. 240- 52 This invention relates to light supports especially for light buoys, and although the invention is primarily applicable to light buoys, it may be applied to lights on light ships. The term light buoys and the like as used herein and in the claims is intended to embrace such other applications. a

Light buoys normlaly comprise a buoyant body which is anchored and floats in a waterway for the purpose of giving a warning or indication to approaching shipping. The body commonly carries a lantern having a transparent housing disposed around the vertical axis of the buoy and within which is disposed a source of light on said axis, the light from which shines out through a lens, disposed usually around said axis; the light then usually passes out through the housing as a slightly divergent beam in a direction which is more or less horizontal when the buoy is in a vertical attitude at rest.

However, in waterways there is usually a tidal effect or possibly a flow eflect arising from a river; there are waves of varying formations and heights, sometimes created by passing ships; and there are wind conditions. These may causethebuoy to lie in a tilted attitude for a long period and may also cause oscillation and/or spinning of the buoy; As arsult the light is only partially effective, or maybe more or less wholly inefi'ectivefas the main usefulness of a b uoy is during the worst weather ond t ns w en t is important. t at thei shou d be at its strongest and should show in the appropriate directions continuously. The aforesaid water or wind conditions are therefore liable seriously to upset the functioning of the buoy, and one of the chief objects of the present invention is to obviate or mitigate these disadvantages.

According to the present invention I provide a light buoy or the like, comprising a mounting for a light source and a lens, at least the lens being mounted to pivot universally relative to the vertical axis of the buoy so as to tend to maintain its attitude in spite of tilting movements of the buoy or the like.

More specifically according to the present invention I provide a light buoy or the like, comprising in combination a lens-surrounding housing, and, a lens mounted to pivot universally relative to the housing so as to tend to v maintain its attitude in spite of tilting movements of the buoy or the like and housing.

Preferably the lens is mounted by two superimposed carriages movable respectively on arcuate guides extending mutually at right angles.

One embodiment of the invention will now be described simply by way of example wtih reference to the accompanying drawings in which:

Fig. 1 is a plan of a light buoy on the line II of Fig. 2 and with the lens removed for clearance, V

Fig. 2 is a sectional elevation on the line II-II of Fig. 1 but with the lens incorporated, and

Fig. 3 is a sectional elevation on the line IIII II of Fig. 2.

Now with reference to the drawings, the light buoy is in the main of conventional construction and its lantern has a lens-surrounding or enclosing housing of generally cylindrical shape, having a frame 4 with a lighttransmitting cylindrical window 5 therearound. Said window may be transparent, for example, of Perspex (registered trademark) or coloured as desired. The axis of the housing is normally vertical and coincident with the vertical axis of the buoy.

The lens is of conventional construction being likewise of generally hollow cylindrical shape with a vertical axis, the lens at its mid-part 6 being part-spherical and at its upper and lower parts 7 of saw-toothed shape in vertical section. The light source is disposed in the middle of the lens on the vertical axis and is energised through a mounting fixed to the buoy. The lens-enclosing housing carries at its lower part a pair of arcuate guide rails 9 (hereinafter called the lower guide rails), which are fixed to the lantern frame 4, lie in parallel vertical planes, and are curved about a point lying on a horizontal axis through the centre of the light source. A lowercarriage 10 is provided with two pairs of wheels 11 on the underside which run on the two lower guide rails, said wheels 11 each being formed with a flange 12.

The carriage 10 in turn is provided on its upper part with two guide rails 14 (hereinafter called the upper guide rails), likewise curving in arcs of circles lying in vertical planes and centered about a horizontal axis extending through the centre of the light source; and thus the upper guide rails 14 are disposed in planes at right anglest'o the planes containing the lower guide rails. Said upper guide rails 14 carry an upper carriage "15 mounting the lens and provided with two pairs of wheels 16, having flanges 17.

The lower and upper carriages each have depending extensions 19, 20 respectively extending downwardly beneath the respective guide rails, and these serve to limit the arcuate movement of the carriages by abutting on stops 13, .18. The extreme position of 19 is indicated in chain-dotted lines in Fig. 3 showing in this example a permitted movement of 20. However, in p act ce it has b sa qund desir b e o. fi but r 2 24. on said extensions 19, 20 for cushioning, and if these are fitted the maximum arcuate movement is reduced for example to 15 as likewise indicated in Fig. 3.

Extensions 19, 20 are also shown provided with keepers 21, 22 secured thereto for the purpose of preventing substantial tipping of the carriages, as in such event they would abut the underside of the respective guide rails.

The lower guide rails 9, the lens-enclosing housing and the light source, are thus all fixed on the buoy, but the lens, and the upper and lower guide rails and carriages are free to move relative thereto as units in a universal fashion. Thus the beam from the lens may remain substantially horizontal despite oscillation or tilting movements of the light buoy.

Weight may be added to either or both of the carriages but the objective is to maintain the radius of gyration of these units as small as possible while the distance between the centre of gravity and the centre of oscillation may be increased. The lens and upper carriage have one set of values resulting in a certain frequency of natural oscillation while the lens and upper and lower carriages complete have a different set of values resulting in a slightly slower frequency of natural oscillation. Provided the resultant of any movement of the buoy in the direction of movement of the appropriate carriage is slower than the natural frequency of oscillation of that carriage then the carriage should maintain itself in a level position. If the other carriage functions in a similar manner the lens of course also remains level. Each unit operates as a compound pendulum whose natural period T is given by the formula where C is a constant, K is the radius of gyration, and a is the distance between the centre of oscillation and the centre of gravity.

As'a result of the invention not only is the lens capable of maintaining its attitude when the buoy tilts for a considerable length of time, but as the lens may have comparatively small weight and relatively small radius of gyration, it is found that its natural period may generally be fast enough to avoid or mitigate oscillation forces imposed on the buoy by wave motions. As a result it is possible to have a light on which one can rely as being in the correct attitude at practically all times.

The invention can moreover be fitted to certain existing lanterns without having to make substantial modifications to the lanterns.

In a modification the light source may be mounted to move with the lens, being connected to its source of energy through flexible connections.

I claim:

1. A light support especially for light buoys comprising a body subjected to tilting movement, a mounting for a light source, a lens disposed around said light source mounting and adapted to transmit a light beam from the source, said light source mounting being positioned to locate the light source at the middle of said lens, and means mounting said lens for universal pivotal movement relative to said body and about the location of said light source as centre, whereby in spite of tilting movement of said body the lens and the light beam passing therethrough tend to maintain a level attitude.

2. A light support according to claim 1, in which said means mounting said lens comprises an upper carriage carrying the lens, a pair of upper arcuate guide rails on which said upper carriage is adapted to run, a lower carriage carrying said upper guide rails, and a pair of lower arcuate guide rails mounted on said body and on which said lower carriage is adapted to run, said upper and lower guide rails extending at right angles to each other and having a common centre of curvature at ap-" proximately the light source.

3. A light support according to claim 2, in which said lens and the upper carriage together have a frequency of natural oscillation faster than that of the lens and upper and lower carriages together.

4. A light support according to claim 2, in which said light source is fixed to said body and moves therewith.

5. A light support according to claim 3, in which the light source is mounted so as to move with the lens and relative to said body.

6. A light support according to claim 2, including stop means to limit the movement of the upper and lower carriages on their respective guide rails.

7. A light support according to claim 1, in which the lens is of generally hollow cylindrical shape with a vertical axis, at its mid-part being part-spherical and at its upper and lower parts of saw-toothed shape in vertical section.

8. A light buoy, comprising a body subjected to tilting movement, a light source, a hollow cylindrical lens disposed around said light source and adapted to transmit a light beam therefrom, said light source being mounted at the mid-point of said lens, and means mounting said lens for universal pivotal movement about said light source and comprising two superimposed carriages movable respectively on arcuate guides extending mutually at right angles.

9. A light buoy according to claim 8, in which the lens and the carriages and upper guides together have a frequency of natural oscillation faster than that of the buoy body.

References Cited in the file of this patent UNITED STATES PATENTS 536,759 Potter Apr. 2, 1895 966,427 Clark Aug. 9, 1910 985,513 Dalen Feb. 28, 1911 1,588,053 Reymond June 8, 1926 1,915,466 Lilly June 27, 1933 2,344,221 Trautner Mar. 14, 1944 2,512,636 Flynt June 27, 1950 FOREIGN PATENTS 631,015 France Mar. 17, 1927 

